The present invention pertains to a heater of a motor vehicle, which heater is operated with liquid fuel, especially a water heater in the form of an auxiliary heater or a parking heater, with a burner and heat exchanger in a housing with cover, in which the connecting branches for the water and air feed and for the water and air return are arranged.
Prior-art above-mentioned motor vehicle water heaters have axial water connecting branches, which are rigidly fastened to the cover and are connected to an external heat exchanger or to the cooling water circuit of the motor vehicle engine via flexible tubes.
Depending on the type of the furnishing, the water heaters are either auxiliary heaters, which contribute to the improvement of the thermal output to the interior of the vehicle and the engine with the engine of the motor vehicle running, or parking heaters, which make thermal output available to the vehicle in an engine-independent manner. The flexible tubes are installed individually depending on the type of the vehicle. Sharper bends in the tubes (i.e., small radii) inherently compromise the service life and the tightness of the heater arrangement. If sharper bends in the tubes are done away with, installation space is often lost.
Based on the above-mentioned state of the art, the object of the present invention is to provide a motor vehicle heater of the type mentioned in the introduction, which makes possible an improved arrangement of the lines especially in the connection area of the heater.
According to the invention, a heater of a motor vehicle is provided which is operated with liquid fuel. The heater is especially a water heater in the form of an auxiliary heater or parking heater. The heater has a burner and heat exchanger in a housing with a cover, in which the connecting branches for the water feed and air feed and for the water return and the air return are arranged. At least one of the connecting branches is designed as a rotatable elbow branch.
The essence of the present invention is that at least one of the connecting branches is designed as a rotatable elbow branch, namely, the feed branch or the return branch. The respective other branch is now preferably designed as a straight branch as according to the state of the art.
However, both connecting branches for the feed and return may advantageously also be designed as elbow branches and arranged optionally in different rotated positions in relation to the housing cover depending on the type of the vehicle.
In particular, the rotatable elbow branch has a securing device against rotation with a lock to secure the elbow branch in a selected rotated position on the housing cover.
The rotatable elbow branch has an outer ring seal in the direction of the outside of the cover and an inner ring seal in the direction of the heat exchanger, the outer and inner ring seals being fixed by the housing cover that can be fastened to the housing. The ring seals may be, in particular, O-rings or flat packings, which may preferably be pretensioned by a spring in the axial direction.
The device for securing against rotation preferably have at least one spring or a projection with an upper locking mechanism away from the housing cover on the circumference of one leg of the elbow branch, which leg can be fastened at right angles to the housing cover, and an axial groove, which is adapted in shape and is associated with the projection, in the cover opening associated with the elbow branch, where the underside of the opening of the cover has a ring locking mechanism, which can be caused to engage the upper locking mechanism of the projection.
The elbow branch may have two projections, preferably offset by 180xc2x0, and the housing cover may correspondingly have two axial grooves, which are preferably offset by 180xc2x0.
The leg of the elbow branch, which leg can be fastened at right angles to the housing cover, has a circumferential flange, which is located at a spaced location from the projection to the outside and acts as an outer axial support of the outer ring seal.
The outer ring seal is preferably axially pretensioned by a spring in a rotary fastened position of the elbow branch on the housing cover and secures the projection in the ring locking mechanism.
With the housing cover mounted on the housing, the elbow branch fastened to the housing cover may come axially into contact with an axial stop at the heat exchanger, especially at the water tank water connection. As a result, an elbow branch, which is arranged in a selected locked position in relation to the housing cover, is prevented from being pushed farther inward against the force of the outer ring seal and from being consequently able to be dislodged from its locked position once the cover is firmly attached to the housing.
It is especially advantageous to provide two projections of different width and two axial grooves with correspondingly different widths. As a result, the elbow branch can be introduced axially into the opening of the cover in a single intended rotation angle position only and can then be rotated laterally in the locking mechanism. If the free leg of the elbow branch, which normally extends in parallel to the outside of the cover, is directly above a fastening point during the axial introduction, in which the cover can be connected and especially screwed to the housing, it is inevitably ensured that the above-mentioned fastening point will always be accessible for the secure, clearance-free fastening of the cover on the housing with the elbow branch rotated laterally in the locking mechanism, and the elbow branch will also be held securely in the rotated position after the clearance-free fastening of the cover on the housing.
Thus, the space requirement for installing heaters in a vehicle can be minimized by the present invention. The lines are arranged in a simple manner in a vehicle, and the lines can be aligned individually and reliably by a simple installation in a given type of vehicle. The molded tubes can be designed as rather uncomplicated tubes. Their service life and tightness are comparatively high, because sharp curvatures can be avoided by means of the elbow branches. Marked package advantages will also arise compared with prior-art water heaters. If desired, different branch diameters may also be provided in a simple manner.